From 1a7a550bfe48528abf7a7e0fc6989b2b4ff0cdb7 Mon Sep 17 00:00:00 2001
From: Jason Turner <jason@emptycrate.com>
Date: Mon, 17 Apr 2023 14:17:48 -0600
Subject: [PATCH] Use globally set CMAKE_CXX_STANDARD if it is set (#620)

---
 cmake/ftxui_set_options.cmake | 10 +++++++++-
 1 file changed, 9 insertions(+), 1 deletion(-)

diff --git a/cmake/ftxui_set_options.cmake b/cmake/ftxui_set_options.cmake
index d608980..90acde4 100644
--- a/cmake/ftxui_set_options.cmake
+++ b/cmake/ftxui_set_options.cmake
@@ -43,9 +43,17 @@ function(ftxui_set_options library)
       $<BUILD_INTERFACE:${CMAKE_CURRENT_SOURCE_DIR}/include>
   )
 
+  # Play nicely if we are being consumed by another project
+  # and use their CMAKE_CXX_STANDARD. Otherwise, fall back to 17
   # C++17 is used. We require fold expression at least.
+  if (DEFINED CMAKE_CXX_STANDARD)
+    set(CXX_STANDARD ${CMAKE_CXX_STANDARD})
+  else()
+    set(CXX_STANDARD 17)
+  endif()
+  
   set_target_properties(${library} PROPERTIES
-    CXX_STANDARD 17
+    CXX_STANDARD ${CXX_STANDARD}
     CXX_EXTENSIONS OFF
   )